Field of the Invention
The present invention relates to torque transmission systems and more particularly to a pinion carrier for planetary gear set and method of making same.
Description of the Prior Art
Typical planetary gear sets contain a pinion carrier and a set of planetary gears. The pinion carrier determines the location of the gears and properly retains the gears in the desired location. There are many variations in the design of the pinion carriers. The design of the carrier is determined by the design of the set of gears and the process selected for manufacturing the carrier.
One-piece carriers are presently formed by machining the components from a solid metal work piece which is formed by casting or molding from materials such as powder metal or cast iron.
Due to the cost involved in producing one piece carriers, the vast majority of carriers are produced from multiple components. Each of the components is typically produced by one of the following methods: 1) stamping from sheet stock; 2) forging; 3) casting; and 4) powdered metal compaction and sintering.
Currently, gear set assemblies employing cold forged or stamped carriers consist of one flat plate and a pedestal comprised of a flat plate having a plurality of outwardly extending legs. The flat plate is positioned on the legs of the pedestal with the legs either abutting the plate, or with the legs protruding through the plate. The assemblage is then welded together. Such a design wherein the legs protrude integrally from only one part of the assembly requires a high degree of deformation in the work piece in the manufacturing process. The longer the legs tend to be, the more difficult it becomes to cold forge the component.
It is an object of the present invention to produce a pinion carrier, which is readily manufactured without any substantial deformation of any of the individual parts prior to final assemblage.